1. Field of the Invention
The present invention relates to an apparatus and method for controlling an electric oil pump, more particularly, to an apparatus and method capable of improving fuel efficiency of a vehicle by optimally controlling an electric oil pump.
2. Description of the Related Art
In order to more efficiently use the power of an engine and a motor, a hybrid vehicle equipped with a hybrid transmission configured by a combination of the engine, the motor and epicyclic gearing may be set to an electric vehicle mode, in which the vehicle is driven by the motor alone, when the vehicle starts or travels in a low-speed section, and to a power branching mode, in which the transmission operates as an electrically variable transmission (EVT), as the speed of the vehicle increases. The hybrid vehicle uses a finite gear ratio as used in a conventional transmission to obtain excellent power performance of the vehicle.
Systems based on the concept above are configured to implement an idle-stop function and maximize regenerative braking so as to improve fuel efficiency and power performance of the vehicle.
In addition, when the hybrid vehicle is driven by a motor generator alone, there is no possibility of generation of exhaust gases from the engine, and the engine can be driven at the point of optimum fuel efficiency. Accordingly, the hybrid vehicle is recognized as eco-friendly vehicle technology for improving fuel efficiency and lowering emissions.
A power transmission apparatus of such a hybrid vehicle is preferably simplified to implement various driving modes such that the driving modes are changed according to the driving situation of the vehicle to improve fuel efficiency of the vehicle through more efficient driving and to improve vehicle driving performance including acceleration.
FIG. 1 illustrates a layout of a transmission of a conventional hybrid vehicle. Referring to FIG. 1, an input shaft 20 connected to a motor 10 is provided with a brake 30.
Before the brake 30 is introduced into the input shaft 20, rotation of a motor generator is stopped through an external power supply source in order to perform overdrive running of the vehicle. However, such a drive method degrades vehicle efficiency and fuel efficiency due to persistent supply of power, and thus a layout for controlling the motor 10 with the brake 30 as shown in FIG. 1 has been provided.
Herein, the brake 30 is operated by hydraulic control through an electric oil pump (EOP). The EOP may serve to provide hydraulic pressure necessary for the transmission brake and to supply oil which is needed to cool and lubricate the motor. However, for the conventional hybrid vehicle to which both the EOP and MOP are applied, technology for generating hydraulic pressure for control of the transmission brake and precisely calculating and controlling the RPM of the EOP needed to cool and lubricate the motor is provided.
The features of the background art described above are merely provided to provide further understanding of the background of the present invention, and should not be construed as suggesting that the present invention corresponds to conventional technology well known to those skilled in the art.